Here's the million dollar question to determine whether you should do that:

Can you barbell squat below parallel while demonstrating good lifting form with heavy weights pain-free? If yes, keep at it.

But the truth is, many athletes can't - and they often hop on the leg press or leg extension machine, thinking that those movements will provide a sufficient alternative to barbell squats.

They don't.

At least not when your goal is to build strong legs that boost your performance on the court or field.

So what would be a better option?

Single Leg Exercises for Twice the Gains

Unilateral movements increase mobility and stability while giving the body a break from heavy spinal loading. That makes them a great choice for improving athletic performance while keeping guys healthy.

Show me an athlete who can split squat or lunge 300+ pounds for reps with a good range of motion and solid technique, and you're looking at a guy who has built impressive lower body strength.

In addition, single-leg movements are quite forgiving for athletes suffering from low back or knee pain. The same can't be said for bilateral squats, leg presses, or leg extensions.

In any case, unilateral strength work should be a part of any smart athletic training program.

Below are six great single-leg squat variations to include in your training.

1. Split Squat

Split squats are the simplest single-leg squat variation out there and a suitable starting point for any athlete.

Once a trainee can demonstrate proficiency with their own bodyweight, we load 'em up.

I prefer starting with dumbbells and moving up in weight as you get stronger. Once you reach the heaviest dumbbells in the gym, add a weight vest for additional resistance.

At most public training facilities, this setup will get you up to around 125 kg / 275 pounds or so in external resistance.

While that sounds like a ton of weight, you're going to run out of dumbbells and vests fairly soon if you attack single-leg training with the same laser-like focus that most people only reserve for driving up their numbers on bilateral (front, back or box) squats.

After maxing out the dumbbells at your gym, the only way to make things more challenging without altering other training parameters like tempo or rest periods will be to use a barbell, which can be loaded with heavier weights indefinitely.

You can also use a trap bar for bigger loads once you've exceeded all the dumbbells/vests at your gym.

The trap bar split squat puts less direct stress on the spine than barbell split squats and can be done without spotters.

2. Rear-Foot Elevated Split Squat

Also known as the Bulgarian split squat, no other leg exercise is as universally hated by my hockey players as the rear-foot elevated split squat.

Sure, doing them for higher reps or using slow eccentrics will lead to some awesome quad pumps. But what people often don't realize is how effectively rear-foot elevated split squats target the glutes. My buttocks are on fire for the next couple of days whenever I perform these.

The perceived difficulty of going heavy on this movement, and the subsequent muscle soreness taking place isn't lost on my athletes, either.

I'm certain that before each new training phase - when we change training exercises and set/rep schemes - some of my athletes convert to born-again Christians, silently letting out a prayer that no Bulgarian split squats will be included in our training program for the next four weeks.

3. Front-Foot Elevated Split Squat

I picked up this exercise while visiting Prentiss Hockey Performance, one of the top training facilities in the US catering to NHL players, in 2014. You never see it done in public gyms; And as far as I'm aware, few strength coaches in the hockey training world use it with their guys.

By elevating the front leg and working over an increased range of motion, you're essentially performing a dynamic hip mobility movement that strengthens your entire lower body.

So you get a "prehab" as well as a strengthening effect at the same time. That's what I call training efficiency.

And to top it all off, the increased range of motion brings the glutes more into play.

4. Reverse Lunge

While nearly every gym-goer is familiar with forward lunges, very few trainees have ever seen, let alone performed, a reverse lunge.

Reverse lunges are a better option for athletes with knee pain - something that often can be traced back to inappropriate training methods in the past - than forward lunges. Since the working leg stays in place, braking forces at the knee are markedly lower.

As such, they work well for building lower body strength in lifters with iffy knees.

5. Valslide Reverse Lunge

This variation doesn't look hardcore but it's brutal on the quads when done heavy enough.

Similar to the regular reverse lunge, the front leg stays in place while you take a step back. This time, however, you place a Valslide or furniture slider under the moving leg, then slide that leg backward.

As you come back from the bottom, focus on "pulling" the back leg up, which stresses the hip flexors to a higher degree than regular reverse lunges.

Some people fear they'll slip when going heavy on these. I've never seen that happen and wouldn't worry about it as long as you're doing smooth, controlled reps. However, you can bump up the number of reps per set a bit just to be on the safe side.

6. Walking Lunge

Behind Bulgarian split squats, walking lunges are the second most hated single-leg exercise at our gym.

Why?

Your legs will burn, you'll have trouble catching your breath after a set, and the muscle soreness you experience in the quads and glutes over the next 24-48 hours are enough to make you wince when sitting down on the toilet.

Wrap up

For years, single-leg exercises have been labeled as "accessory" work, to be performed later in a workout after the supposedly "more important" strength movements.

At worst, they've been dubbed "useless" by old school coaches and lifters still clinging to the dogma that the only proper way to squat is to squat with two feet on the ground and a heavy weight on your back.

But what if those sore knees or that cranky low back aren't made for that?

Do you keep forcing the issue week after week, month after month just because some tough guy on the internet said that you have to barbell squat?

Or do you take a step back, look at the big picture, and realize that better alternatives exist for making injury-free lower body strength and size gains for years to come?

The six single-leg squat variations presented above will help you get there.